Previous studies have linked selflessness to happiness, however nobody had investigated the mechanical link between the two.

In the latest study, participants were placed in two groups: the first, known as the experimental group, was made up of people who promised to spend money on others, while the second group, known as the control group, promised to spend money on themselves.

At the end of the four-week study period, researchers found those in the experimental group reported increased happiness compared to the control group.

Scientists used functional magnetic resonance imaging to look into the brain mechanisms that linked generous behaviour with increased happiness. They discovered that generous decisions activated an area of the brain linked to happiness and the reward cycle.

They concluded that while generous behaviour may be costly - “as it involves the investment of one’s own resources for the benefit of others” - it can increase happiness and could also motivate generosity in the future.

One of the researchers, Professor Phillipe Tobler, from the Department of Economics at the University of Zurich (UZH) in Switzerland, said: “You don’t need to become a self-sacrificing martyr to feel happier. Just being a little more generous will suffice.”